This invention relates to a shaft drive for balloon tired motorcycles and more particularly to an improved driving arrangement for such vehicles.
Recently, it has been proposed to equip motorcycles with large, low pressure balloon tires to adapt them for off the road use. The use of such low pressure tires (tires having pressures in the range of 0.1 to 0.2 kg/cm.sup.2) has great advantages for off the road use. However, certain problems arise in connection with driving the rear wheel. Since the engine and transmission is normally mounted by the frame in a location between the rider's legs, the manner of transmitting drive from the engine output shaft to a rear wheel which may be at least as wide or wider than the frame presents certain difficulties. That is, it the engine output shaft is extended laterally outwardly and either a straight drive shaft or chain drive is employed, the rider's leg position becomes extremely awkward.
In order to offset these deficiencies, it has been proposed to employ a drive arrangement that incorporates an intermediate shaft, one end of which is driven by an inwardly positioned chain from the engine output shaft and the other end of which drives the rear wheel through an outwardly positioned chain. An example of such a chain drive is shown in copending application Ser. No. 632,717, filed July 20, 1984 in the name of Nobuaki Shiraishi, entitled "Offroad Running Motorcycle" and assigned to the same assignee as this application. Although such a drive offsets the deficiencies noted above, it itself has certain difficulties. For example, it is difficult to provide an adjustment for each of the chains. In addition, this type of arrangement has certain other disadvantages inherent with chain drives.
It is, therefore, a principal object of this invention to provide an improved driving arrangement for off the road motorcycles.
It is a yet further object of this invention to provide an improved shaft drive for motorcycles having balloon tired rear wheels.